Device for transferring a material in the form of a film that is applied to a carrier strip onto a substrate

ABSTRACT

A device for transferring a film from a carrier strip onto a substrate includes a housing having a supply reel and an empty reel. A film coated carrier strip is guided over an applicator foot where a clip-type slide element is provided in the region around which the carrier strip is looped. The clip-type slide element is made of a friction-reducing material secured to the applicator foot. The slide element has an elliptical cross-sectional shape so that on transfer of the film onto the substrate the contact pressure region of the slide element bears over an area adjacent to the substrate with interposition of the carrier strip.

BACKGROUND OF THE INVENTION

The invention relates to a device for transferring a material in theform of a film applied to a carrier strip onto a substrate, such as asheet of writing or drawing paper, comprising a housing in which asupply reel for the film-coated carrier strip and an empty reel forreceiving the de-coated carrier strip are arranged, wherein thefilm-coated carrier strip is guided over an applicator foot provided atleast in the region which is looped around by the carrier strip with aclip-type slide element of a friction-reducing material secured to theapplicator foot.

Hand devices of that kind for transferring a film (for example, adhesivestrip, concealing substance, marking ink, etc.) are known. In that case,in order to achieve a smooth motion and good capability of transfer ofthe film onto the substrate various embodiments for the shapes of theapplicator foot are known. Thus, the applicator foot can be equippedwith, for example, an applicator roller which preferably has arubber-elastic running surface. However, as the external diameter of afunctionally effective applicator roller cannot be kept as small asdesired, because a good adaptation to the substrate requires a minimumthickness for the elastic running ring and the rotational mobilitypresupposes a sufficient difference between axle stub and externaldiameter, such an applicator roller has disadvantages. Accordingly, inmost solutions the applicator foot usually has an applicator strip whichhas advantages relative to an applicator roller, as a sharper angling ofthe carrier strip is possible in the transfer phase, whereby thetorn-off piece has less tendency to formation of a wavy edge aftercompletion of the transfer. Thereagainst it is disadvantageous relativeto the applicator roller solution that in the case of the applicatorstrip the carrier strip is guided thereover with a friction couplewhich, in dependence on the respective carrier strip quality, can leadto undesired heavygoing.

In principle, synthetic materials which have a good sliding property areknown, for example polytetrafluorethylenes (PTFE), but which are higherin cost by a multiple than the standard materials usually used for thecomponents of a device of the kind in question. Accordingly, the use ofan applicator foot of polytetrafluorethylene is excluded on costgrounds.

As polytetrafluorethylene is not a true thermoplastic, a loading of theregion, which is effective with respect to guidance, of the applicatorfoot by this high-quality material in a multi-componentinjection-moulding process or a subsequent injection-moulding processhas to be excluded. A conceivable solution, such as gluing theapplicator strip by a self-adhesive foil coated with fluoroplastics, hasin fact been attempted already, but from the viewpoint of productionengineering is unsuitable for mass-produced articles.

A device of the category in question is known from U.S. Pat. No.5,430,904. In this device the applicator foot is provided in the regionwhich is looped around by the carrier strip with a slide element made ofa friction-reducing, rubber-elastic material and fastened to theapplicator foot. This slide element is to improve the transfer of thefilm onto the substrate. In the active pressing segment of theapplicator strip it has a rotationally symmetrical curved profile and asan inevitable result thereof a small linear contact region with thesubstrate. It has proved that on transfer of the adhesive layer onto asubstrate the adhesive layer easily tears, so that the carrier stripslides over the substrate on a silicon layer and the drive isinterrupted.

SUMMARY OF THE INVENTION

It is accordingly the object of the invention to so improve a deviceaccording to the category that a faultless transfer of the film onto thesubstrate is guaranteed in return for smallest possible outlay.

In accordance with the invention this object is met in the case of adevice of the kind denoted in the introduction in that the slide elementhas an elliptical cross-sectional shape in such a manner that ontransfer of the film onto the substrate the contact pressure region ofthe slide element bears over an area against the substrate withinterposition of the carrier strip.

According to the invention it is possible in an unexpectedly simplemanner to create, by simple change in the cross-sectional shape of theslide element, a substantially larger contact area between the slideelement on the one hand and the substrate on the other hand so as tomake available a sufficient contact pressure area, which ensures thatthe adhesive material layer does not tear off so that a faultlessfunctioning of the device is given. The slide element itself can in thisconstruction nevertheless be decidedly small, for example it can beproduced as a semi-finished product of the smallest dimensions (forexample, with an external diameter of 1 to 1.2 millimeters and 0.2 to0.3 millimeters wall thickness), in that it is cut off to the desiredlength, slit in longitudinal direction and then spread apart and pushedonto the applicator foot. This can be carried out automatically insimple manner.

With particular advantage it is proposed in that case that the slideelement consists of polytetrafluorethylene (PTFE) as this material has aparticularly good sliding property. Obviously also materials withcomparable characteristics can be used.

Moreover, it is proposed with advantage that the end portion, whichreceives the slide element, of the applicator foot similarly has across-sectional shape which is elliptical at least regionally. The slideelement can then be produced in particularly simple manner as theinternal profile thereof can largely correspond with the externalprofile. It is then, in addition, securely held at the applicator foot.

BRIEF DESCRIPTION OF THE INVENTION

The invention is hereinafter described in more detail by way of examplewith reference to the drawings, in which:

FIG. 1 is a perspective illustration of an applicator foot of a deviceaccording to the state of the art, without slide element,

FIG. 2 is a side view partly in section of the applicator foot of adevice according to the invention, without slide element,

FIG. 2a is a section of the slide element for the device according toFIG. 2,

FIG. 3 is the front view of the applicator foot,

FIG. 4 is a side view partly in section of the applicator foot accordingto FIG. 2, with pivoted-in extension arm and slide element in place,

FIG. 5 is a front view of FIG. 4, and

FIG. 6 is a perspective illustration of the applicator foot.

DETAILED DESCRIPTION

A conventional device according to the state of the art for transferringa material in the form of a film applied to a carrier strip onto asubstrate is illustrated, without slide element, in FIG. 1, althoughonly with the parts significant for the invention, namely an applicatorfoot which is denoted generally by 1. This applicator foot 1 is equippedwith an applicator strip 2, around which a coated carrier strip 3,coming from a supply reel, which is not illustrated, of the device isguided. After the transfer of the coating 4 onto a substrate it ispassed on as an empty strip 5 to a winding-up reel, which is notillustrated. It has emerged that such an applicator foot 1 is notsatisfactory with respect to easy motion of the device and faultlesstransfer of the film onto the substrate.

According to the invention another design of the applicator foot istherefore provided, this being illustrated in FIG. 2 et seq.

An applicator foot according to the invention of a device in accordancewith the invention is denoted generally by 6 in the figures. Thisapplicator foot 6 comprises strip guide ears 7 between which the carrierstrip is guided. The applicator foot 6 is provided with an extension arm9 pivotably hinged to the applicator foot 6 by way of a film hinge 8.This extension arm 9 is formed at its end as a receiving profile member(end portion 10) for a clip-type slide element 15. Grooves 13 are cutout of the applicator foot 6 and serve the purpose of achieving a detentlatching of the extension arm 9 to the applicator foot 6 in thepivoted-in position of the extension arm 9, for which purpose detentdogs 12 are provided on the extension arm 9 at both outer sides.

As evident from FIG. 3, the extension arm 9 comprises ribs 11 which are,for preference, longitudinally oriented. These ribs 11 serve, inconjunction with a selection of an elastic material, for examplepolyolefin, to ensure a particularly good contact between the applicatorstrip (end portion 10) and possible unevennesses of the substrate plane.As the clip-type slide element 15 of polytetrafluorethylene is similarlyelastic, it is thereby achieved that even in the case of a non-planarsubstrate the entire transfer width of the strip is subjected topressure and, similarly to an elastic roller, formation of bubbles isreliably prevented so that a smooth coating onto the substrate takesplace.

Essentially to the invention the slide element 15 has, as particularlyevident from FIGS. 2a and 4, an elliptical cross-sectional shape suchthat on transfer of the film to the substrate the contact pressureregion 15 a of the slide element 15 bears over an area against thesubstrate with interposition of the carrier strip. Moreover, it isprovided that the end portion 10, which receives the slide element 15,of the applicator foot 6 or the extension arm 9 similarly has across-sectional shape which is elliptical in at least regionally, thisregion being denoted in FIG. 2 by the reference numeral 10 a.

FIGS. 4 and 5 show the extension arm 9 in pivoted-in and lockedposition. In that case the film hinge 8 is pivoted through about 90° .The clip-type slide element 15 placed on the end portion 10 of theextension arm 9 is additionally fastened in the manner that abutmentsteps 16 and 17 are provided at the applicator foot 6 or extension arm9, whereby the slide element 15 is secured against rotation. It isachieved through contact of the extension arm 9 with a cross-member 18of the applicator foot 6 that the free end portion 10 of the extensionarm 9 can flexibly spring out in its entirety.

The applicator foot 6 with detent dogs 12 notched in the grooves 13 andcorrespondingly fastened slide element 15 is recognisable in front viewfrom FIG. 5. Through abutments 19 at the applicator foot 6 it isachieved that, in the case of possible excessive applied pressure byinappropriate handling of the device, the applicator strip formed by theslide element 15 reaches a final end abutment which is so dimensionedthat the slide element 15 always protrudes by a few tenths of amillimeter beyond the profile of the strip guide ears 7, so that thetransfer function is remains secured. Moreover, it is recognisable thatthe ends 20 of the clip-type slide element 15 are advantageouslyarranged to be recessed in recesses 21 of the strip guide ears 7,whereby it is ensured that the carrier strip is kept away from the ends20 possibly compressed by the cutting to length of the tube from whichthe slide element 15 is preferably produced.

In FIG. 6 the entire applicator foot 6 is illustrated again infunctional position, i.e. with pivoted-in and locked extension arm 9,and in particular in the end position of the clip-type slide element 15with securing against rotation and longitudinal displacement.

The invention is obviously not restricted to the illustratedembodiments. Further refinements are possible without departing from thebasic concept. The slide element 15 obviously does not have to have anexactly elliptical cross-sectional shape, it being essential that itforms an areal contact pressure region 15 a.

What is claimed is:
 1. Device for transferring a material in the form ofa film applied to a carrier strip onto a substrate, such as a sheet ofwriting or drawing paper, comprising a housing in which a supply reelfor the film-coated carrier strip and an empty reel for receiving thede-coated carrier strip are arranged, wherein the film-coated carrierstrip is guided over an applicator foot provided at least in the regionwhich is looped around by the carrier strip with a slide element of afriction-reducing material secured to the applicator foot, characterizedin that the slide element has an elliptical cross-sectional shape insuch a manner that on transfer of the film onto the substrate thecontact pressure region of the slide element bears over an area againstthe substrate with interposition of the carrier strip, the ellipticalcross-sectional shape including a large diameter surface between twosmall diameter surfaces, and the large diameter surface being outermostof the applicator foot.
 2. Device according to claim 1, characterized inthat the slide element consists of polytetrafluoroethylene (PTFE). 3.Device according to claim 2, characterized in that the end portion,which receives the slide element, of the applicator foot similarly has across-sectional shape which is elliptical at least regionally.
 4. Deviceaccording to claim 3, characterized in that the applicator foot includesabutment steps mounted for securing the slide element against rotation.5. Device according to claim 2, characterized in that the applicatorfoot includes abutment steps mounted for securing the slide elementagainst rotation.
 6. Device according to claim 1, characterized in thatthe applicator foot includes abutment steps mounted for securing theslide element against rotation.
 7. Device according to claim 1,characterized in that the end portion, which receives the slide element,of the applicator foot similarly has a cross-sectional shape which iselliptical at least regionally.